Flow proportioning apparatus



March 28, 19,44. H. ZIEBOLZ FLow PRoPoRTIoNING APPARATUS Filed July 9,'1941 Patented Mar. 28, 1944 2,345,521 FLOW PBOPORTIONING APPARATUSHerbert Ziebolz, Chicago, Ill., assigner to Askanla Regulator Company,

of Illinois Chicago, lll., a corporation Application July s, 1941, sensiNo. 401,661

z claims. (c1. 1x1-.164)

'Ihls invention relates to improved apparatus for supplying combustionsupporting air by conduit means as a function of the theoretical airrequirements of a plurality of separate fuels having differenttheoretical air requirements and heating values while at the same timeaugmenting or diminishing such theoretical supply by an amount whichdepends on other factors which may or may not vary in accordance withthe rates of fuel flow and in which the flow of at least one of thefuels is adapted to be automatically controlled; and the'flow of theother fuel varies. The main idea is to provide improved summarizing andproportioning means, including automatic control means for the flow ofat least one of the fuels, whereby the air ow may be variedautomatically in response to changes in the flow of the other fuel orfuels to produce a desired comb furnace or the like.

ion atmosphere in` a The problem is to so ad- Just the controlled supplyof air that a desired percentage of excess or deficiency of air isprovided regardless of the variations in the ratios of the fuels and oftheir rates of flow. By com trolled supp i of air is meant the air whichis introduced through air-conduit means independently of air admittedwith the fuel and/or air which enters into a furnace by infiltration andfrom Iother uncontrollable sources.

Heretofore, it has en suggested that rates of fuel flow be summarized bymeans of fuel` flow meters or by pilot air flows which are directlyproportional to the individual B. t. `u. rates of fuel flow and thetotal air proportioned to the sum of the individualfuel ows in terms oftheir heating values. The design of such mechanisms is based on the factthat a definite amount of air is required for theoretically com` tennsof its B. t. u. value. In the operation of .plete combustion of a givenquantity of fuel in industrial furnaces or boiler furnaces a number offactors must be taken into consideration which y renders the supply ofthe calculated or exactamount of air necessary for theoreticallycomplete combustion improper. Such factors do not vary as a directfunction of the rate of fuel flow but present different values atdifferent rates of fuel flow. vSome of these factors are, for example.air used to atomize liquid fuels or `primary air used for conveyingpulverized fuel, which air is not subject to control by the well knownair control apparatus. Such factors may be termed burner factors." Thecalculated amount of air, which would be supplied by the controlapparatus to support theoretically complete combustlon of a single fuel,modified by the amount of air which nnds its wayinto the v burnerinstallation by reason of these factors, is referred to hereinascompensated air requirements" of that fuel. If more than one fuel l issupplied, the calculated amount of air which -into the furnace, othersources of air of de- `terminable amounts admitted to the furnace. orthe desired condition of the furnace atmosphere. All of these factorsare subject to variations which are not direct functions of the rate oftotal fuel supply. They may be termed fur nace factors. 'I'hese furnacefactors may require lfurther adjustment in the total compensated airrequirements called for by the fuels. The total compensated airrequirements, thus modined by these furnace factors, is herein termedadjusted total air requirements."

It is therefore a further and more specific obk' ject of this inventionto provide automatic control and proportioning means which takes intoaccount all such variable factors and varies the total supply of air asa function of the sum of the flowsof at least one primary fuel, suppliedat a constantrate, anda secondary fuel supplied at a variable,uncontrolled rate.

'I'his invention involves certain improvements over my copendingapplication Ser. No. 401,666. nled July 9, 1941.

Other aims and advantages of the invention will, appear in the'specification, when considered in connection with the accompanyingdrawing, wherein the figure is a diagrammatic illustration of one formof apparatus embodying-the invention applied to the lcontrol of airv fortwo fluid fuels.

Referring particularly to the drawing, the control mechanism is shown asbeing applied to control the amount of combustion supporting air inaccordance with the compensated air requirements for two separate fuelsof different character flowing through individual conduits I0 and iiandthe combustion air is supplied for both fuels through a single conduiti2, the conduits leading -to a furnace, not shown. One of il is shown ashaving a constriction i3 and a y butterfly control valve Il. Theposition oi the valve is adapted to be automaticallyl varied and theflow maintained by a jet pipe regulator i5, here shown as being of thewell known hydraulic type. A pair of pipes I6 and i'l are connected toopposite sides of the constriction and lead to pposite sides of adiaphragm i8 connected to act on one side of the pivoted jet pipe i 5.The force exerted by the diaphragm acts in opposition to a spring i9,the compression of which is controlled by a movable cam 20 of variablecontour. The cam is shown as being composed of a multiplicity ofrelatively adjustable, slotted pieces clamped together by a bolt 2i andsecured to a carriage 22 which is slidably mounted in fixed bearings.The contour of this cam is adjustable to take into account the foregoingvariable factors involving the fuelso that the adjusting movements arealways proportional to the compensated air requirements for the fuel,departing from a directly proportionalrelationship between thetheoretical amount of air called for and the rate of flow of the fuel.The regulator has a ratio slider 23 which may be employed to vary theratio of the compensated air requirements for the fuel in accordancewith variations in the density, chemical analysis and viscosity of thefuel, as well as other factors. The force exerted on the jet pipe bythed diaphragm duo to the diierential pressure on opposite sides o f theconstriction i3 is always counteralanced by the force of the spring torestore thejet pipe to neutral position and maintain the ow of fuelconstant. The carriage 22 on which the cam 20 is mounted, is adapted tobe adjusted longitudinally by means of al hand wheel 24 carrying apinion meshing with a rack 25 connected to the carriage. Of course, themanual adjustment may be eiected in any one of a number oi ways.

The cam 20 is set so that its adjusting movement from a zero positionrepresenting zero fuel flow corresponds with the compensated amount ofair for the rstor primary fuel supplied at any desired constant rate andthe rate of iiow of the fuel is maintained by the regulator, the jetpipe of which-acts through a pair of pipes 26 and 2l on the piston 28 ofa servomotar connected to the butteriiy valve i4 to maintain the rate offuel flow through the critica constant. The adjusted position ormovement of the cam is indicated by means of a pointer 29 cooperatingwith a scale 3b reading in terms of the compensated quantity of air forthe fuel l'or fuel rate. The carriage is shown as being connected bymeans of an arm 3i and link 32 to a crank arm 33 mounted on one shaft ofa differential gear 34. Such a dl'erential gear is shown in detail in myaforesaid copending cation.

The conduit i i for the second fuel is also shown as having aconstriction 35 across which difieren.. tial pressure is created tooperate aow responsive device having a jet pipe 36 through pipes 31 and38 and a diaphragm 39 in the same manner as the jet pipe i5. The forceexerted by the diaphragm on the jet pipe is opposed by a spring 40, thecompression of which is controlled by an adjustable cam 4i made of aplurality of pieces which take into account variations in the chemicalanalysis of the fuel, viscosity changes, density changes, etc. The jetpipe is shown as operating a servo-motor 43 of the piston type through apair of pipes 44 and 45. The cam 4i is mounted on a carriage 45 which isslidably mounted in xed bearings similar to carriage 22. The carriagehas a rack 4l meshing with a gear 48 which is operated by theservo-motor 43 through a crank 49. The carriage is also shown asoperating a pointer 50 cooperating with a scale 5i which is diierentialgear 34 by means of an arm 52 and like cam 20 and its adjusted contouris determined by the compensated air requirements for the second fuel atits dierent rates of ilow or for each increment of change in its rate offlow. The flow responsive device also has a ratio slider 42 adapted tochange the percentage or ratio of the air to the fuel. In addition, theratio slider permits the introductionof correction factors link 53through a second crank arm 54 on the second shaft of the differentialgear. As explained in the aforesaid application, the diiierential gearsummarizes the adjusted and variable movements of the two cams and thesum of these movements is imparted through it to a spur gear 55, whichoperates a rack 56 on a slidable carriage 51, similar to the carriage48. The carriage 51 also carries a cam 58 made like cams 20 and 4i andwhich is shaped to proportion the supply of air in accordance with themovements imparted to it and to take into account air infiltration intothe furnace. In other words, its contour is adjusted to vary theproportion between the total compensated air requirements and theadjusted total air requirements for each increment o1' change in thetotal fuel ilows. The carriage operates a pointed 59 cooperating with ascale 60, to indicate the sum of the total, compensated air requirementsof the separate fusie before the movement imparted to the gear 55 and,through it, to the cam 58 is the sum of the movements imparted by theseparate cams 2li through the differential gear 34.

Now, the flow of air in conduit i2 is shown as being controlled by abuttery valve @i which is actuated by a piston type servo-motor 52. Theservo-motor is connected by pipes 63 and 54 to be operated by a jet piperegulator 65, also having a ratio slider 5B whereby the air ratio may bechanged at will. The cam 58 acts on one side of the jet pipe through aspring'i and changes the lling of the regulator to control the air nowthrough the conduit I2. The spring El acts on the jet pipe in oppositionto a diaphragm 58 on the opposite side of the jet pipe, and thepcsitionV of the diaphragm is controlled by.' the pressure differentialacross a constriction 69 in the air ccnduit i2 acting through pipes 10and 'il on opposite sides of the diaphragm.

As the spring is compressed by the movement oi the cam to the right, thejet pipe turns clockwise and thereby causes the servo-motor to open thevalve Bi until the increase in air now creates a diierential pressureacross the constriction 69 which is sumcient to counterbalance the forceof spring 57. Thus, the air now is so controlled that it is directlyproportional to the air cam movement, as modified by the compensatingadjustments. which movements are directly proportional to the sum of theindividual compensated air requirements of the individual fuels. Theadjustments o1' the ratio slider 66 permit variations in the ratiobetween the controlled air flow and the total compensated airrequirements,

thus controlling the percentage of excess or deflciency offthe totalair.

In the operation of the apparatus, the hand wheel 2l is used to set thefirst fuel cam 20 in terms of the rate of iow of compensated airrequirements, as observed on the scale I0, to maintain a desired rate offuel flow. This adjustment imparts movement through the arm Il on oneshalt or the diierentiai gear to the air cam Il and the cam 2li remainsfixed in its adjusted position, due to. friction of the parts. As theflow or the second fuel in lthe conduit Il changes, the ilotv responsivedevice operates the servo-motor H3 and thus imparts control movementthrough the arm 54 on the second shaft of the differential gear which isadded to the adjusted movement or the iii-st shaft and thus additionallymoves the air cam 59 to change the control setting of the air flowregulator t5. This setting will correspond to the total compensated airrequirements for the first and second. :nels and will be variedautomatically as the flow of the second fuel Varies.

It Willtbe understood that the regulators, flow responsive deviceservo-motors and the cams may be mounted on any suitable support, suchas a table. The stroke of the cams can be made the same for all controlsby choosing the necessary gear ratio of the dill'erential gears and thecams may be guided for straight line movement in any convenient manner,for example, by Wheeled carriages or the like. Moreover, the 1ndicatorsmay be either mechanical or electrical and all of them may be located atany convenient point.

it will be understood that the improved apparatus embodying theinvention may be applied to the control of the combustion air for anynumber ci fuels by using an additional differential gear for eachadditional fuel as disclosed in the aforesaid copending application.

Clbvlcusly, the present invention is not restricted to the particularembodiment thereof herein shown and described. Moreover, it is notindispensable that all the features oi' the invention be usedconjolntly, since they may be the'ccntour of said cam cluding a memberconnected to the vflow responsive device, to convert said impulses intocontrol movements of said member from a zero position corresponding tozero flow of the second fuel, which movements are directly proper tionalto compensated quantities of air for the second fuel at its varyingrates of dow: summarizing means connected to the manually movable memberand the control means to summarine said movements; and a regulatorcontrolled by said summarizing means and connected to said air conduitto vary the supply of air.

2. Apparatus, as set forth in claim l, wherein the manually movablecontrol member has adjustable elements arranged to be adjusted so as toproduce dinerent settings of the resulator for any given amount ofmanual movement of the control member.

3. Apparatus, as oet forth in claim l, wherein the manually movablecontrol member has 'adjustable elements arranged 'to be adjusted so asto produce different settings of the regulator for any given amount ofmanual movement of the control member, and wherein a cam of adinstablecontour and shaped to allow for air infiltration into the furnace isconnected to be actuated by the summarizing means to operate theregulator which is controlled by said summarlaing means, and wherein thelast mentioned regulator is' provided with means to multiply theadjusted total air now by any given factor.

4. Apparatus, as set forth in claim 1, wherein the fuel regulator andthe now responsive device are of the hydraulic type having jet pipes andthe manually movable control member to set the fuel regulator. and thecontrol means connected to the now responsive device both comprisespring loading cams of adjustable contour to make compensations in thetheoretical air requirements "for the respective fuels. l

5. Apparatus, as set forth in claim l, wherein the regulator controlledby the summarizing means is of the hydraulic type having a movable Jetpipe-and a loading cam of adjustable contour and is directly operated bysaid summarizing and connected to operate the regulator, beingadjustable to call for an adjusted total amount of air for eachincrement of its movement thereby allowing for employed advantageouslyin various combinations and sub-combinations.

What is claimed is:

1. Apparatus for proportioning the supply of combustion air to that ofseparate fuels having different heating values comprising, incombination, individual conduits for the air and fuels: a regulatorconnected to one of the fuel conduits to control the flow therein; amanually movable control member associated with and connected to set theregulator to maintain the fuel ilow constant at a predetermined rate:said member being so constructed and arranged that its :total movementfrom a zero position corresponding to zero fuel now is proportional to acompensated quantity 'of air corresponding to the rate of now of thefuel; a flow responsive device connected to a second fuel conduitthrough which the rate of flow varies and arranged to be operated byimpulses derived from the flow of the second fuel: control means, in-'air innltration in to a furnace.

6. Apparatus, as set forth in claim 1, wherein the fuel regulator isprovided with ratio varying means so constructed that the movement ofthe manual control member may be multiplied by a given factor for anyconstant ratio of fuel ow, and wherein the now responsive device alsoincludes a ratio varying member to multiply the control movementsimparted thereby to its associated member by a given factor for allratlos of :dow of the second fuel. Y

7. Apparatus, as set forth in claim 1, wherein the manually movablecontrol member has .adjustable elements arranged to be adjusted so trolmember.

T ZIEBOLZ.

